In last week’s blog post, we discussed some of the shared connections between people and dogs in regards to sleep apnea.
But we also have a lot in common with dogs when it comes to the temporomandibular joints, the joints that connect the jaw to the skull and play a key role in the common and painful condition known as temporomandibular joint disorder (TMJ). A recent study found striking similarities (and contrasts) between the canine and human temporomandibular joints, and could help inform future TMJ treatments.
Dr. Berry’s Bulldog
A Joint that Bonds Dogs, People
Researchers in the oral biology department at Damanhour University in Egypt last year conducted a detailed comparative analysis of the dentition and temporomandibular joint in dogs to those of humans. Canine mouths vary in many obvious ways from human mouths, including overall structure and number of teeth. However, we share a number of similarities:
- Dogs and humans are diphyodont, meaning we both get two sets of teeth; the deciduous, or “baby,” teeth and subsequent permanent teeth
- The dental tissue of canine and human teeth bears close resemblance, though dogs’ teeth have thinner layers of enamel
- Humans and dogs both possess brachydont teeth, or teeth with relatively short crowns that display above the gum line and are rooted deep in the jaw bone
Another is the temporomandibular joint, which humans, dogs and other mammals use to varying degrees in biting, chewing and swallowing. Despite the parallels, there are significant differences between the canine temporomandibular joint and the joint in humans; and researchers believe form and function are directly tied to the structural differences.
Temporomandibular Joint Functions
In humans, the temporomandibular joint plays a role in how we eat, speak and even sleep. As the comparative study notes, dogs use their temporomandibular joints primarily in biting and swallowing food; they chew little compared with people.
Researchers believe that these differences in functionality have played a role in the anatomical structure of the temporomandibular joint in dogs and people over time. In dogs, the joint is essentially a hinge for opening and closing with little flexibility for lateral movement, but researchers pointed out the joint is comparatively strong.
The temporomandibular joint in humans is a form of synovial joint, a particularly flexible joint that connects bones via a fluid-filled capsule. In people, the joint supports a broader range of motion, but it lacks the canine temporomandibular joint’s strength. Researchers indicated they hope their study will lead to a better understanding of how the temporomandibular joints work and contribute to improved treatment options in the future.
TMJ in People and Dogs
TMJ is a common, but commonly misdiagnosed, problem that affects millions of Americans. It is associated with symptoms that include recurring migraine-like headaches; jaw and facial discomfort; the jaw locking or popping; and pain throughout the necks, shoulders and back.
While there is little research into TMJ in dogs, there are a number of jaw disorders that can afflict dogs, and some of the symptoms are the same. Pet MD recommends contacting a veterinarian if your dog shows difficulty opening or closing its mouth; seems in pain when eating or eats on one side of the mouth; or suddenly seems to lose interest in eating.
As for people, it’s a good idea to contact a knowledgeable TMJ dentist if you experience any of the symptoms discussed here, especially chronic headaches that have otherwise gone undiagnosed. There are a number of comfortable, effective TMJ therapies available.
Denver neuromuscular dentist Dr. Kevin Berry has helped many people find lasting relief from TMJ pain. Please call (303) 691-0267 to schedule your appointment at the TMJ Therapy & Sleep Center of Colorado.